Hand dryers are commonly used in lavatories to aid users to dry hands after washing. The conventional hand dryer usually has a motor and a heating structure. The motor draws in air which is heated by the heating structure and generates a powerful heated airflow to dispel or dry residual moisture on user's hands.
However, compared with paper towel, the hand dryer takes more time and consumes electric energy when in use. Hence how to increase hand drying efficiency to reduce energy consumption is a big issue in the industry. To increase hand drying efficiency, one approach is to boost motor efficiency to generate a stronger airflow pressure to dispel the moisture from user's hands. Another approach is to enhance the efficiency of the heating structure and increase airflow exit temperature to dry the moisture on the hands easier. The stability of heated airflow passage in the hand dryer often is overlooked. Hence there still leaves a lot to be desired in terms of airflow exit efficiency.
A desired airflow passage in the hand dryer can produce a higher airflow exit efficiency to dispel or dry the moisture from user's hands at a shorter time. Use duration of the hand dryer not only affects user's convenience also impacts optimal energy utilization. If the air drawn by the motor can be transformed to effective exit airflow, energy waste can be greatly reduced.
The commonly used hand dryers, open through type or wall-mounted type, such as R.O.C. patent No. I266629 entitled “Hand drying apparatus”, No. 254101 entitled “Multi-function dryer”, or U.S. Pat. No. 7,039,301 do not focus on the size of the hand dryer. The hand dryers they proposed are quite bulky. Due to environment and space constraints, their applicability and installation are restricted. There is still a need to develop a compact hand dryer with a higher exit airflow efficiency to improve the problems mentioned above.